Operating dynamo-electric machines.



No. 78,307. Patented Nov. ll, I902.

F. H. JEANNIN.

OPERATING DYNAIO ELECTRIC MACHINES.

(ApplicLtion filed Oct. 28, 1991.)

(No Model.)

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UNITED STATES PATENT OFFICE.

FRANK II. JEANNIN, OF SOHENECTADY, NEIV YORK, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

OPERATING DYNAMO-EL ECTRIC MACHINES.

SPECIFICATION forming part of Letters Patent No. 713,307, dated November1 l, 1902.

Application filed October 28, 1901. Serial No. 80,177. (No model.)

To (DZ/Z whom it may concern: ing shown as an eight-pole machine and theBe it known that I, FRANK I-I. JEANNIN,.a machine 2 as a ten-polemachine. The arcitizen of the United States, residing at Schenmature ofthe machine 1 is provided with a ectady, county of Schenectady, State ofNew three-phase winding andis connected through 55 5 York, have inventedcertain new and useful suitable leads with the bus-bars 4. The ma-Improvements in Operating Dynamo-Electric chine 2 may have its armatureprovided with Machines, (Case No. 2,358,) of which the fola windingsimilar to that of machine 1 or diflowing is a specification. ferent, asdesired. In this instance the ar- In synchronizing a set ofdirect-connected mature is supposed to be provided with a 60 1oalternating current dynamo electric maquarter-phase winding, thefourleads extendchines with the corresponding members of ingtherefrombeing represented as connected another similar set or with sets of mainsdifto the quarter-phase bus-bars 5. The fieldficulty frequently ariseswhen the machines windings of the two machines may be reof the set havedifferent numbers of poles. spectively excited in any desired manner; 65In such cases when one machine comes into but I here represent them asboth receiving synchronism it is the usual experience to current from a.pair of exciter bus-bars supfind that the other machine is not insynplied with direct current from any suitable chronism, and vice versa.In order to avoid source. (Not shown.) troubles of this character, Idiscard entirely Another motor-generator set is represented 70 allsynchronism-indicating devices and conby the machines 7 and S,mechanically connect the machines directly in circuit through nected toa shaft 9. These respective matension-reducing devices, such ascompensachines are of a construction similar to that tors or step-downtransformers. IVhen a set of the firstdescribed motor-generator set andof machines is thus connected to another set like the first set receivetheir field-exciting 75 or to sets of mains, current immediately flowscurrent from any suitable source. In this into each machine, tending tobring the rot-atstance they are represented as deriving the ing memberof each machine up to synchrocurrentfrom the same set of exciting-leads6. nism. In case there is a tendency for one In synchronizing the twomotor-generator machine to come into synchronism before the sets the onewith the other the eight-pole mem- 8o other, then large currents, whichact to preher 8 of one set is connected through a comvent synchronism ofthe first machine, flow pensator 10 to the bus-bars 4, to which the tothe latter machine until both machines eight-pole member 1 of the otherset is concan go into synchronism at the same time. nected. In asimilarmannertheten-pole ma- It may, of course, happen that these crosschine 7of one set is connected by a compen- 85 currents may flow first in onemachine and sator ll to the bus-bars 5, to which the tenthen in theother until synchronism of both pole machine 2 of the other set isconnected. is obtained. To prevent excessive currents Suitable switches,represented at 12 and 13,

from flowing, I make use of the tension-reare of course provided, sothat the set of maducing devices to which I above referred. chines 7 8may be connected or disconnected 90 In the drawing I have representeddiafrom the respective sets of mains whenever grammatically oneembodiment of my invendesired. tion, and in the claims hereto appended IIn synchronizing the two sets of machines have pointed out what Ibelieve to be the the one with the other one set of machinesnovelfeatures of the invention. as, for example, the set 1 2may be supposed 5Referring to the drawing, the machines to be already running. Theswitches 12 13 marked 1 and 2 represent the members of a of the otherset are then closed, thus connectmotor-generator set, the machines inthis ining together the corresponding machines of stance being directlyconnected and the shaft the two sets. The machines 7 8 thus receivebetween them represented by the dotted lines current from the respectivesets of mains and :oo 3. The machines are of different numbers run up inspeed until each machine falls into of poles, the machine 1 in thisinstance besynchronism. In case one machine drops or tends to drop intosynchronism before the other it is immediately dragged out ofsynchronism, so to speak, by cross-currents flowing in the othermachine, and this operation is repeated by one machine or the otheruntil both come into synehronism together. The

step-down compensatorsto wit, the three-,

phase compensator and the quarter-phase compensator 1lserve to preventexcessive currents from being drawn from the mains4 5 While the machinesare being synchronized.

It will be observed that in synchronizing in accordance with myinvention no synchronism-indicating devices are necessary, the machinesmerely being connected in circuit through compensators until synchronismis attained, upon which the compensators may be cut out of circuit.

During the operation of synchronizing the field-circuits of the machines7 and 8 may be left open and after synchronism is attained then closed.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is-

1. The method of synchronizing sets of direct-connectedalternating-current dynamoelectric machines having difierent numbers ofpoles, which consists in connecting together the corresponding membersof each set through tension-reducing devices, whereby the resulting flowof current operates to bring the machines into synchronism.

2. The method of synchronizing a plurality of sets of direct-connecteddynamo-electric machines, the members of each set having differentnumbers of poles, which consists in causing currents to flow between thecorresponding members of the diiferent sets until the respective membersof the set or sets to be synchronized come into synchronismsimultaneously.

3. The method of synchronizing a set of di rect-connectedalternating-current dynamoelectric machines the currents of which arenormally of difierent frequency, which consists in connecting bothmachines to the circuits with which they are to be synchronized, therebypermitting the motor action of the resulting flow of currents to bringthemachines into synchronism simultaneously.

In witness whereof I have hereunto set my hand this th day of October,1901.

FRANK H. JEANNIN.

Witnesses:

BENJAMIN B. HULL, ALEXANDER D. LUNT.

